Carbon collectors are regularly also used as a so-called sliding strip for energy transfer from a catenary wire to a vehicle, such as for example a locomotive. In the presence of severe wear or damage to the carbon collector, considerable damage to the catenary wire or an overhead line can occur, amongst other things. Locomotives are therefore regularly equipped with a sensor device, which brings about a lowering of the sliding strip with the carbon collector or a pantograph when a certain wear limit of the carbon collector is exceeded or damage occurs to the carbon collector. The sensor device comprises a sensor element which can be constituted as a fluid-sealed channel or as a tube profile in the carbon collector, wherein the sensor element is acted upon by compressed air. When the wear limit is reached, the channel or the tube profile start to be ground and compressed air escapes. The pressure loss is detected by the sensor device, after which a lowering of the pantograph takes place.
In some cases, use is made in carbon collectors of stable tube profiles which are inserted in a longitudinal recess on the underside of or inside the carbon collector. The problem arises here that a tube profile, constituted for example by a metal tube, is not reliably damaged, i.e. triggering of the sensor device and lowering of the pantograph is not brought about in all envisaged cases. If, for example, pieces of carbon break out from the carbon collector caused by a fault in the catenary wire, the tube profile may be exposed and in some cases severely deformed. Especially in the case of sufficiently elastic and metallic tube profiles, this deformation does not necessarily lead to direct damage to a tube profile wall that could produce an escape of compressed air. In order to avoid damage to overhead lines, however, it is necessary for the pantograph to be lowered immediately after such damage to the carbon collector.
The problem underlying the present invention, therefore, is to propose a sensor element or a carbon collector with a sensor element, which produces an improved response of a sensor device in the event of damage to the carbon collector.